diff options
Diffstat (limited to 'include/asm-generic/cmpxchg.h')
| -rw-r--r-- | include/asm-generic/cmpxchg.h | 87 |
1 files changed, 80 insertions, 7 deletions
diff --git a/include/asm-generic/cmpxchg.h b/include/asm-generic/cmpxchg.h index e0449af91f60..8a361834dc25 100644 --- a/include/asm-generic/cmpxchg.h +++ b/include/asm-generic/cmpxchg.h @@ -1,16 +1,87 @@ +/* + * Generic UP xchg and cmpxchg using interrupt disablement. Does not + * support SMP. + */ + #ifndef __ASM_GENERIC_CMPXCHG_H #define __ASM_GENERIC_CMPXCHG_H -/* - * Generic cmpxchg - * - * Uses the local cmpxchg. Does not support SMP. - */ #ifdef CONFIG_SMP #error "Cannot use generic cmpxchg on SMP" #endif -#include <asm-generic/cmpxchg-local.h> +#include <linux/irqflags.h> + +#ifndef xchg + +/* + * This function doesn't exist, so you'll get a linker error if + * something tries to do an invalidly-sized xchg(). + */ +extern void __xchg_called_with_bad_pointer(void); + +static inline +unsigned long __xchg(unsigned long x, volatile void *ptr, int size) +{ + unsigned long ret, flags; + + switch (size) { + case 1: +#ifdef __xchg_u8 + return __xchg_u8(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u8 *)ptr; + *(volatile u8 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u8 */ + + case 2: +#ifdef __xchg_u16 + return __xchg_u16(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u16 *)ptr; + *(volatile u16 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u16 */ + + case 4: +#ifdef __xchg_u32 + return __xchg_u32(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u32 *)ptr; + *(volatile u32 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u32 */ + +#ifdef CONFIG_64BIT + case 8: +#ifdef __xchg_u64 + return __xchg_u64(x, ptr); +#else + local_irq_save(flags); + ret = *(volatile u64 *)ptr; + *(volatile u64 *)ptr = x; + local_irq_restore(flags); + return ret; +#endif /* __xchg_u64 */ +#endif /* CONFIG_64BIT */ + + default: + __xchg_called_with_bad_pointer(); + return x; + } +} + +#define xchg(ptr, x) \ + ((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))) + +#endif /* xchg */ /* * Atomic compare and exchange. @@ -18,7 +89,9 @@ * Do not define __HAVE_ARCH_CMPXCHG because we want to use it to check whether * a cmpxchg primitive faster than repeated local irq save/restore exists. */ +#include <asm-generic/cmpxchg-local.h> + #define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) #define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) -#endif +#endif /* __ASM_GENERIC_CMPXCHG_H */ |